NO. 8 INSECT ABDOMEN SNODGRASS 09 



The exposed part of the ninth abdominal segment of Amblydisca 

 (fig. 28 A, IXT), as in Homoptera generally, consists of the large 

 tergum. The ventral part of the segment is membranous and deeply 

 concave, forming a cavity in which are lodged the proximal parts of 

 the third valvulae and the shaft of the ovipositor. 



The ovipositor consists of two pairs of broad, thin valvulae, the 

 first and the second (fig. 29 A, iVl, 2VI), mostly concealed be- 

 tween the wide third valvulae ( jF/) . The planes of the valvulae are 

 vertical. The first valvulae lie close against the outer surfaces of the 



IXT 



Fig. 29. — Muscles of the ovipositor of Amblydisca gigas. 



A, right half of ovipositor and ninth segment, mesal view. 



B, right first valvifer and first valvula, mesal view. 



second pair, and the two on each side are firmly but movably attached 

 by the usual interlocking grooves and ridges. The second, or inner, 

 valvulae are conspicuously serrate along their dorsal margins (A, 

 2VI) ; at their bases they are united with each other by a membranous 

 fold, but for most of their length they are free, though closely ap- 

 pressed. Each first valvula has two proximal rami (figs. 28 C, 

 29 B), a ventral outer ramus {rwlo) attached to the anterior angle 

 of the first valvifer (iVlf), and a dorsal inner ramus (rivli) which 

 expands in a small triangular plate (in) attached to the lower an- 

 terior angle of the ninth tergum (fig. 28 C, n, IXT). The second 



